1. Field of the Invention
The present invention generally involves the field of technology pertaining to devices for mounting an electric motor to an appliance. More particularly, the invention relates to a device for mounting an electric motor to a wall of an appliance wherein the wall separates two different temperature zones.
2. Description of the Prior Art
A refrigerated compartment, such as found in a domestic refrigerator or freezer, is normally provided with a fan blade or impeller for the purpose of circulating cold air derived from the evaporator of the refrigeration system. The compartment is typically formed from walls of insulated material and provided with an access opening that is closed by a hinged door. The fan blade is disposed within a ducting which provides communication between the evaporator and the compartment. In some conventional installations, an electric motor is secured to the exterior of an insulated wall of the compartment. The output shaft of the motor is disposed through a hole in the wall and into the ducting for attachment to the fan blade.
This known configuration for mounting an electric motor and an associated fan blade has been proven disadvantageous for several reasons. The disposition of the motor on the exterior side of the compartment wall necessarily requires the utilization of a long power output shaft for supporting the fan blade. Because of the extended length of the output shaft, its rotation is generally unstable, particularly towards the end of the shaft on which the fan blade is mounted. In this arrangement, the bearing assembly for the output shaft is required to be disposed adjacent the motor, thereby subjecting the bearing assembly to possible detrimental effects caused by heat generated during operation of the motor. Moreover, the hole in the compartment wall through which the output shaft extends also requires a rotating seal, in order to prevent heat from entering the compartment and imposing a greater load on the refrigeration system.